Most Americans don’t think twice about tossing back a diet soda, an easy sacrifice compared, say, to giving up a bag of chips. But the controversy swirling around the artificial sweetener Splenda, used in many diet drinks and other foods, may quell our sugar-free indulgence – and help us rethink how to handle sweet-tooth issues. We all know that sugar calories are empty ones. But are we risking our health – and even our waistlines – by leaning on sugar substitutes? A recent study at Duke University offers alarming new answers…

Nearly 200 million Americans eat foods laced with sugar substitutes. And half of those people consume four such products a day. Sugar substitutes, or artificial sweeteners, are far sweeter than sugar; only a small amount creates the same sweetness we crave – with far fewer calories.

But the Duke University study – and others – may make the fake sugar route to slimness seem less appealing, even risky. In a 24-week study on rats, the Duke researchers found that sucralose, the key ingredient in Splenda, significantly reduced the “good” intestinal bacteria in the rats’ guts and hampered the release of certain enzymes that enable us to absorb oral medications. “Good” bacteria like acidophilus and bifidobacterium (you may have seen those mentioned on some yogurt labels) help us absorb food and minerals. They also help crowd out disease-causing bacteria and help prevent their growth.

The rats also had increased pH levels in their feces, a test of acidity. As distasteful as that may sound, you should know that acidic stool may increase the risk of colorectal cancer, lactose intolerance, or indicate the presence of Rotavirus, which causes about 90% of infections in humans. Human feces are normally alkaline, not acidic. In other words, sucralose in amounts of 1.1-11 milligrams per kilogram of weight appears to be disturbing to guts – at least to rat guts – in alarming ways. The Food and Drug Administration (FDA) says that the acceptable daily amount of sucralose is 5 milligrams per kilogram.

Splenda’s manufacturer, McNeil Nutritionals, dismissed the Duke findings as the “Sugar Association-funded rat study,” saying the conclusions were inconsistent with the data presented. It also says that the study did not meet the usual standards for scientific research and that it lacked control groups that would allow comparison. The Sugar Association, the lobbying group for the sugar industry, financed Duke’s study.

Since its introduction to the market in late 1999, Splenda has overtaken nearly two-thirds of the estimated $1.5-billion artificial sweetener market, pushing down sales of aspartame (Equal) and table sugar. Before the FDA approved sucralose as an artificial sweetener in 1998, the federal agency conducted its own testing of sucralose on rats and concluded that the sugar substitute was safe.

But sucralose isn’t the only artificial sweetener on the hot seat. In yet another rat study at Purdue University in Lafayette, Ind., researchers found that rats given yogurt sweetened with saccharin ate more calories, and gained more weight and body fat than rats who ate yogurt sweetened with sugar. And the saccharin-swilling rats didn’t cut back on calories later. The researchers speculate that the artificial sweetener confuses the body’s normal way of registering sweet food and calories. Usually, when we start to eat, our metabolism gets in gear, linking sweetness to incoming calories. But when the food tastes sweet but ushers in no calories, that basic mechanism gets confused, perhaps registering all sweets as without calories or undermining the ability to know when we’re full. That, in turn, may lead to overeating and decrease the ability to burn off calories. Other artificial sweeteners are likely to have the same effect, the researchers surmise.

Their findings correlate with evidence that people who drink more diet drinks tend to be at greater risk for obesity and for metabolic syndrome, a collection of health risks such as high blood pressure and insulin resistance that boost the risk of diabetes and heart disease.

Taking a More Natural RouteOf course, human studies are essential to determine just how applicable both studies’ findings are for people. But in the meantime, what’s a person to do? Could natural sweeteners be a solution?

Those that have attracted attention lately include stevia and xylitol, although neither has been approved by the FDA as an artificial sweetener. Each is derived from natural sources such as certain shrubs, corn, sugar cane and birch wood.

Stevia comes from the leaves of a South American shrub and has been used as a flavor enhancer for centuries. A high-intensity sweetener, stevia is 300 times sweeter than table sugar. But the FDA allows it to be sold in the United States only as a dietary supplement, not an artificial sweetener. Without that approval, stevia cannot be labeled as such in foods or drinks, although it is found in some drinks and teas at health food stores. Cargill Inc., the largest U.S. agricultural company, is currently working with Coca-Cola to create a stevia-based sweetener, which the two companies plan to market in countries, such as Japan, Brazil and China, which have approved stevia.

To date, stevia appears to have a clean safety record. Stevia was used for centuries in South America and in Japan since the 1970s, and no significant side effects have cropped up. And a 1997 animal study by the National Institute of Health Sciences in Tokyo, Japan, also found no adverse affects.

Xylitol belongs to a family of sweet-tasting additives known as sugar alcohols, including sorbitol, lactitol, mannitol and isomalt, which are used to sweeten “sugar-free” foods such as gum, candy and cookies. They are derived from natural sources, such as corn cobs, sugar cane and birch wood. The sugar alcohols contain fewer calories than sugar, do not promote tooth decay, and are not easily absorbed by the body. But overdo it with these sweeteners, and you may notice you’re a bit gassy with loose bowels. No other side effects have been found in humans. But, oddly, xylitol can be fatal to dogs, causing insulin to spike – and it’s also toxic to dogs’ livers. To keep this in perspective, chocolate, raisins and grapes are also dangerous for dogs.

Xylitol has about the same sweetness as table sugar. It cools your mouth with a minty flavor, making it the top choice among sugar alcohols as a flavoring for sugar-free products. The FDA has approved xylitol’s use in foods made for diabetics, such as gum, mints and syrups, but, again, not as an artificial sweetener.

Sweet Issues to Think AboutSo what is the potential harm of using artificial sweeteners? The concerns fall into four main camps:

1. Skepticism about the safety data.Critics point out that much of what we know about sweetener safety comes from industry-sponsored studies. But most independent food chemists find the sweeteners to be safe and the FDA has incorporated generous safety margins into its recommendations.

2. A misread of “sugar-free.”Consumers may mistakenly assume that “sugar-free” means calorie-free. Although most diet sodas may be calorie-free, many other foods – such as sugar-free yogurt, cookies, cocoa, drink mixes, confections and desserts – are not. Removing sugar does not mean that milk products, soy proteins and fats have skipped town too, and those can pile on calories.

3. Nutrient-dead diet soft drinks.Drinking diet colas from dawn to dusk offers hydration (unless they’re high in caffeine, a diuretic) but no nutrition. Diet drinks are no substitute for healthy drinks such as water, fruit juices or low-fat milk.

The upshot: If you want a diet soda now and then or a food made with artificial sweetener, that’s fine. But you’re better off drinking lots of water and eating a sensible diet that includes a variety of fruits, vegetables, whole grains, lean meats, plant oils, and dairy foods, not just a concentration of sugar-free foods.

Sweet facts:

Americans swallow the equivalent of 20 teaspoons of sugar a day.

Even Teddy Roosevelt defended sugar substitutes, declaring 100 years ago that “anybody who says saccharin is injurious to health is an idiot!”

Eating or drinking sweets may lower stress by lowering the production of a stress-related hormone.

What’s Your Sugar IQ?

Sugar and spice and everything nice...that's what little girls are made out of, right? Actually, too much of the sweet stuff could be giving you BIG problems, namely with the scale. Being smart about your sugar intake can help you cut hidden calories and make better food choices. Take this quiz to test your sugar IQ.

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